In this article, we proposed a new way to achieve monostable and bistable characteristics of composite layers based on liquid crystal elastomer (LCE). A smart trilayer composite structure is fabricated using LCE and acrylic elastomer, which can have several morphologies. It keeps flat at room temperature and can deform into a monostable saddle or bistable cylinder surface in response to simple temperature changes. The reversible deformation can be controlled through two parameters including geometrical size and actuation strain. The LCE can be programmed to generate different actuation strains by different formulas during synthesis or different mechanical stretches during UV radiation. The deformed morphology for different sample sizes and actuation strain is calculated using Finite element simulation. By comparison with the experimental results, we confirm that the phenomena can be captured through numerical simulations. Furthermore, to have a quantitative understanding, we use numerical simulation to calculate the deformation of the composite structure by tuning these two parameters and give a morphological portrait illustrating the relationship between the deformed shape and control parameters.

When a soft solid such as rubber, gel and soft tissue is subject to hydrostatic tension, a small cavity inside the solid expands. For a neo-Hookean solid, when the hydrostatic tension approaches a critical value: 2.5 times its shear modulus, the initially small cavity can expand unboundedly. Such a phenomenon is usually referred to as cavitation instability in soft solids. Several recent experiments have shown that fractures may occur in the material when the hydrostatic tension is far below the critical value. In this article, we study a spherical cavity with a ring crack on its wall and inside a neo-Hookean elastomer subject to hydrostatic tension. We compute the energy release rate associated with the extension of the ring crack, for both pressure-control and (cavity) volume-control loading modes. We find that for the pressure-control mode, the energy release rate increases with the increase of the crack size as well as the magnitude of pressure; for the (cavity) volume-control mode, with a fixed cavity volume, the energy release rate increases with the increase of the crack size when the crack is short; the energy release rate maximizes for an intermediate crack size, and decreases with the increase of crack size when the crack is long. The results obtained in this article may be helpful for understanding cavitation-to-fracture transition in soft solids subject to different loading conditions.